KR20060017862A - Glass fibres for reinforcing organic and/or inorganic materials, composites enclosing said fibres and used compounds - Google Patents

Abstract

The invention relates to reinforcing glass fibres whose composition comprises the following components expressed in percentage by weight within the following limits: 50-65 % SiO2, 12-20 % AI2 O3, 13-16 % CaO, 6-12 % MgO, 0-3 % B2O3, 0-3 % TiO2, < 2 % Na2O + K2O, 0-1 % F2, < 1 %Fe2O3. The inventive fibres consist of glass exhibiting an excellent compromise between the mechanical properties thereof in terms of a specific Young modulus and the fusion and fibre properties.

Description

Glass fibers for reinforcing organic and / or inorganic materials, composites enclosing said fibers and used compounds}

FIELD OF THE INVENTION The present invention relates to glass "reinforced" yarns (or "fibers"), i.e. yarns suitable for reinforcement of organic and / or inorganic materials and which can be used as woven yarns, these yarns being the bottom of a bushing. Obtained by a process consisting of mechanically drawing a stream of molten glass located in and flowing from an orifice which is generally heated by resistance heating.

More precisely, it is an object of the present invention to obtain glass yarns having high specific Young's Modulus and having particularly advantageous quaternary compositions of the SiO ₂ -Al ₂ O ₃ -CaO-MgO type.

The field of glass reinforcement yarn is a very special field of the glass industry. These yarns are made from specific glass compositions, and the glass used must be able to be drawn in the form of filaments of several microns in diameter using the process mentioned above, and a continuous yarn can be formed that can fulfill the reinforcing role.

In certain applications, in particular in the field of aeronautics, it is an object of the present invention to obtain large parts which are suitable for operation under kinetic conditions and as a result can withstand high mechanical stresses. These parts are generally based on organic and / or inorganic materials and, for example, glass yarn-shaped reinforcements which generally comprise at least 50% by volume.

The improvement of the yield and mechanical properties of these parts is achieved by the improvement of the reinforcement density p which increases the mechanical performance of the reinforcement, in particular the constant or lower inelastic coefficient (E / p).

In the case of glass reinforcing yarns, the properties of the reinforcing materials depend mainly on the composition of the glass being produced. Common glass yarns for strengthening organic and / or inorganic materials are mostly made of E-glass and R-glass.

E-glass yarns are widely used in the form of reinforcement or textiles. The conditions under which E-glass can be fibrous are quite favorable, the working temperature corresponding to the temperature when the viscosity of the glass approaches 1000 poise is relatively low, about 1200 ° C., and the liquidus temperature is about 120 ° C. below the working temperature The vitrification rate is low.

E-glass compositions in accordance with ASTM D578-98 standard for applications in the electronics and aeronautics fields include 52 to 56 weight percent SiO ₂ , 12 to 16 weight percent Al ₂ O ₃ , 16 to 25 weight percent CaO, B ₂ 5 to 10 weight percent O ₃ , 0 to 5 weight percent MgO, 0 to 2 weight percent Na ₂ O + K ₂ O, 0 to 0.8 weight percent TiO ₂ , 0.05 to 0.4 weight percent Fe ₂ O ₃ and F ₂ 0 to Contains 1% by weight.

However, the inelastic coefficient of E-glass is about 33 MPa · kg ⁻¹ m ³ , which is not suitable for the intended use.

Other E-glass reinforcements that do not optionally contain boron are described in the ASTM D 578-98 standard. The composition of these yarns is 52 to 62% by weight SiO ₂ , 12 to 16% by weight Al ₂ O ₃ , 16 to 25% by weight CaO, 0 to 10% by weight B ₂ O ₃ , 0 to 5% by weight MgO, Na ₂ O + K ₂ O 0-2 weight percent, TiO ₂ 0-1.5 weight percent, Fe ₂ O ₃ 0.05-0.8 weight percent and F ₂ 0-1 weight percent.

Although the fiberization conditions of the boron-containing E-glass are less favorable than the fiberization conditions of the boron-containing E-glass, the fiberization conditions of the boron-containing E-glass are economically acceptable. The inelastic coefficient has a performance level equivalent to that of E-glass.

In addition, boron and fluorine-free E-glass with improved tensile strength is known from US Pat. No. 4,199,364. The glass contains lithium oxide in particular.

R-glass is known to have high mechanical properties and an inelastic coefficient of about 35.9 MPa · kg ⁻¹ m ³ . However, melting and fibrosis conditions are more limited than the mentioned E-type glass, so that the final cost thereof is higher.

Compositions of R-glass are described in French Patent Publication No. 1,435,073. The composition comprises 50 to 65% SiO ₂ , 20 to 30% Al ₂ O ₃ , CaO 2 to 10% and MgO 5 to 20%, CaO + MgO is 15 to 25% by weight and SiO ₂ / Al ₂ O ₃ is 2 to 2.8 and MgO / SiO ₂ is less than 0.3.

Other attempts have been made to increase the mechanical strength of glass sand, but in general, to determine the fiberization of the glass sand, processing required the presence of a fiberizing plant that had to be made more difficult or deformable.

Thus, there is a glass reinforcement that requires a cost as close as possible to the cost of E-glass and exhibits almost the same mechanical properties as R-glass in terms of performance level.

One object of the present invention is to provide a continuous glass reinforcement yarn which has satisfactory melting and fibrosis properties, in particular in terms of inelastic modulus, to the same size as R-glass, in order to economically obtain the reinforcement yarn. To provide.

Another object of the present invention is to provide an inexpensive glass yarn containing no lithium oxide.

These objectives are 50 to 65% by weight of SiO ₂ , 12 to 20% by weight of Al ₂ O ₃ , 13 to 16% by weight of CaO, 6 to 12% by weight of MgO, 0 to 3% by weight of B ₂ O ₃ , TiO ₂ to 3 A glass yarn consisting essentially of less than ₂ % by weight, ₂ % by weight of Na ₂ O + K ₂ O, 0-1% by weight of F ₂ and 1% by weight of Fe ₂ O ₃ is achieved.

Silica (SiO ₂ ) is one of the oxides which forms a network of glass according to the invention and plays an essential role in the stability of the network. Within the gist of the present invention, when the silica content is less than 50% by weight, the viscosity of the glass becomes too low, increasing the risk of devitrification during fiberization. If the silica content exceeds 65%, the viscosity of the glass becomes very high and difficult to dissolve. Preferably, the silica content is 56 to 61%.

In addition, alumina (Al ₂ O ₃ ) constitutes a network former for the glass according to the invention and, in combination with silica, plays an essential role in terms of modulus. Within the gist of the limits defined in accordance with the present invention, if the alumina content is reduced to less than 12% by weight, the liquidus temperature rises, while if the content of the alumina is excessively increased to more than about 20% by weight, it will be devitrified It is dangerous and increases in degree. Preferably, the content of alumina in the selected composition is 14-18 weight percent. Advantageously, the content of silica + alumina is at least 70% by weight, as a result of which the inelastic coefficient can be obtained at useful values.

Lime (CaO) is used to control the devitrification of the glass and to adjust its viscosity. CaO content is preferably 13 to 16% by weight.

Like CaO, magnesia (MgO) also acts as a viscosity reducing agent and has a beneficial effect on the inelastic modulus. The MgO content is 6 to 12% by weight, preferably 8 to 10% by weight. The CaO / MgO weight ratio is preferably 1.40 or more, advantageously 1.8 or less.

Also preferably, the Al ₂ O ₃ and MgO content is at least 24% by weight, thereby obtaining a very satisfactory inelastic modulus and a good fiberization state.

Boron oxide (B ₂ O ₃ ) acts as a viscosity reducing agent. Its content in the glass composition according to the invention is limited to 3% by weight, preferably 2% by weight, in order to avoid volatilization and pollutant release problems.

Titanium oxide acts as a viscosity reducer to help increase the inelastic coefficient. It may be present as an impurity (the content in the composition then 0 to 0.6% by weight) or may be added intentionally. In the latter case it is necessary to use non-standard batch materials, which increases the cost of the composition. In the context of the present invention, it is advantageous to intentionally add TiO ₂ , where the content is less than 3% by weight, preferably less than 2% by weight.

Na ₂ O and K ₂ O can be introduced into the compositions according to the invention in order to limit the vitrification and possibly to reduce the viscosity of the glass. However, the Na ₂ O and K ₂ O content should be within 2% by weight in order to avoid an unfavorable decrease in the hydrolysis resistance of the glass. Preferably, the composition contains less than 0.8% by weight of these two oxides.

Fluorine (F ₂ ) may be present in the composition to assist in melting and fiberizing the glass. However, its content is limited to 1% because, if this limit is exceeded, there may be a risk of contaminants being released and the furnace refractory bricks corrosive.

Iron oxide (expressed in the form of Fe ₂ O ₃ ) is generally present as an impurity in the composition according to the invention. The Fe ₂ O ₃ content should be less than 1% by weight, preferably less than 0.8% by weight, in order not to unacceptably impair the color of the yarn and the work of the fiberizing plant, especially heat transfer in the furnace.

The glass sand according to the present invention does not contain lithium oxide. These oxides, in addition to high prices, negatively affect the hydrolysis resistance of the glass.

Preferably, glass yarn 56 to 61% by weight of SiO ₂ , 14 to 18% by weight of Al ₂ O ₃ , 13 to 16% by weight of CaO, 8 to 10% by weight of MgO, 0 to 2% by weight of B ₂ O ₃ , TiO ₂ Essentially 0 to ₂ % by weight, less than 0.8% Na ₂ O + K ₂ O, 0 to 1% F ₂ and less than 0.8% Fe ₂ O _{3 by} weight.

The Al ₂ O ₃ / (Al ₂ O ₃ + CaO + MgO) weight ratio of the composition is variable from 0.4 to 0.44, with particular preference being preferably less than 0.42, whereby a glass having a liquidus temperature of 1250 ° C. or less can be obtained.

Glass yarns according to the invention are obtained from glass having the above composition using the following process. A plurality of molten glass streams exiting a plurality of orifices located at the base of one or more bushings are drawn in the form of one or more continuous yarn bundles and then the filaments are combined into one or more yarns and collected on a moving support. This may be a rotating support when the yarns are collected in package form, or when the yarns are made of chopped strands by a device that also serves to stretch them or serve to stretch them to form a mat. When sprayed by the device, it may be a parallel moving support.

Thus, the yarns obtained may take various forms such as continuous yarns, chopped strands, braids, tapes or mats, optionally after other conversion operations, which yarns consist of filaments with a diameter of approximately 5-30 μm.

The molten glass supplied to the bushing is obtained from a pure batch material, or more commonly from a natural batch material (ie possibly containing trace amounts of impurities), which batch materials are mixed in an appropriate amount before melting. . The temperature of the molten glass is conventionally adjusted to enable fiberization and to avoid de-vitrification problems. Prior to combining the filaments into yarn form, the filaments are generally coated with a foil composition to prevent filament wear and to allow for easier introduction of the filaments into the material to be reinforced later.

The composite obtained from the yarn according to the invention comprises at least one organic material and / or at least one inorganic material and glass yarn, at least part of which is according to the invention.

The following examples are intended to illustrate this without limiting the invention.

The molten glass having the composition shown in Table 1 (expressed in weight percent) was stretched to obtain a glass yarn made of glass filament having a diameter of 17 μm.

The temperature at which the viscosity of the glass becomes 10 ³ P (dPa.sec) is represented by T _log eta _{= 3} .

The liquidus temperature of the glass is denoted by the T _liquidus , which corresponds to the temperature at which the growth rate of the most flame retardant phase that can be devitrified in the glass is zero, and thus corresponds to the melting point of this devitrified phase.

The table shows the inelastic coefficient values corresponding to the ratio of the elastic modulus (measured using the ASTM C 1259-01 standard) to the density of the glass surface used in the measurement.

Measurements for E-glass and R-glass are shown as comparative examples.

This shows that the examples according to the invention show an excellent compromise between the melting and fibrosis properties and the mechanical properties. This fiberizing property is particularly advantageous when the liquidus temperature is at least 1280 ° C. or higher, lower than the liquidus temperature of the R-glass. The fiberization range is particularly pronounced when the difference between T _{logη = 3} and the T _{liquid phase} is about 10 to 50 ° C.

The magnitude order of the inelastic coefficient of the composition according to the invention is the same as that of R-glass and is substantially higher than that of E-glass.

Thus, using the glass according to the invention achieves the same level of mechanical properties as for R-glass, while it is worth noting that the fiber treatment temperature is substantially lowered to approach the level obtained for E-glass.

Glass yarns according to the invention are advantageously cheaper than R-glass yarns which can be replaced for certain applications, in particular for aviation applications, for reinforcing helicopter wings or for optical cables.

Claims (8)

50 to 65% by weight of SiO ₂ , 12 to 20% by weight of Al ₂ O ₃ , 13 to 16% by weight of CaO, 6 to 12% by weight of MgO, 0 to 3% by weight of B ₂ O ₃ , TiO ₂ 0 To 3 wt%, less than 2 wt% Na ₂ O + K ₂ O, 0 to 1 wt% F _{2 and} less than 1 wt% Fe ₂ O ₃ , glass reinforced yarn. The glass reinforced yarn of claim 1, wherein the MgO + Al ₂ O ₃ content is greater than 24 wt%. The glass reinforced yarn according to claim 1 or 2, characterized in that the content of SiO ₂ + Al ₂ O ₃ is 70% by weight or more. The glass reinforced yarn according to claim 1, wherein the Al ₂ O ₃ / (Al ₂ O ₃ + CaO + MgO) weight ratio is 0.40 to 0.44, preferably 0.42 or less. The glass reinforced yarn according to any one of claims 1 to 4, characterized in that the CaO / MgO weight ratio is at least 1.40, preferably at most 1.8. The method according to any one of claims 1 to 5, wherein 56 to 61 wt% SiO ₂ , 14 to 18 wt% Al ₂ O ₃ , 13 to 16 wt% CaO, 8 to 10 wt% MgO, and B ₂ O ₃ 0 to 2% by weight, 0 to 2% by weight of TiO ₂ , Na ₂ O + K ₂ O less than 0.8% by weight, F ₂ 0 to 1% by weight and Fe ₂ O ₃ less than 0.8% by weight Glass reinforcement. A composite comprising a glass reinforced yarn and at least one organic and / or inorganic material, characterized in that it comprises a glass reinforced yarn as claimed in claim 1. 50 to 65 wt% SiO ₂ , 12 to 20 wt% Al ₂ O ₃ , 13 to 16 wt% CaO, 6 to 12 wt% MgO, 0 to 3 wt% B ₂ O _3, 0 to 3 wt% TiO ₂ , A glass composition suitable for the preparation of glass reinforced yarns, which essentially comprises less than ₂ % Na ₂ O + K ₂ O, 0% to 1% F _{2 and} less than 1% Fe ₂ O ₃ .